The Eastern U.S. Coast Faces A Major Hurricane Threat Within Days

I honestly sat here for a moment trying to think of a title that doesn't sound too exaggerated or hype-filled. I am very sensitive to that because I do often worry about hype that I see around hurricanes. There are real issues with social "media-rologists" posting long range information beyond acceptable skill range so that they can get clicks, retweets, or the "Internet" fame of saying "see I told you." Having said all of that, I think we have passed the "uh oh" threshold with Tropical Storm Florence. The National Hurricane Center and our most reliable models are forecasting the storm to intensify to a Hurricane Florence (again). While that in itself is worrisome, the storm is projected to become a major hurricane (category 3, 4, or 5) and forecasts are aiming it in the direction of a region from northern Florida to Virginia. As much as I want to "wish cast" a different scenario, I am struggling to find, using all of my years of education and experience as a meteorologist, a scenario in which this storm doesn't impact mainland U.S.

Current tropical systems in the Atlantic Basin. Florence looks to be a threat to the U.S.NOAA

I keep looking for models to show me viable "OTS" (Out to Sea) options for #Florence. Unfortunately, they are becoming fewer and less likely. ☹️ Please stay updated on the forecast, and have a hurricane plan. #flwx #scwx #gawx #ncwx #vawx

He is absolutely correct. There is plenty of warm ocean water ahead of Florence, and it is projected to move into a more conducive environment for intensification. Over the past few days, the storm encountered a significant amount of wind shear and dry air. This led to temporary weakening of the storm. However, the National Hurricane Center 5:00 AM (AST) discussion provides some ominous words that catch my "meteorological" eye,

(an east-west ridge) This large-scale feature is expected to steer Florence in a general westward direction during that time.........The global models agree on this general change in the synoptic-scale flow pattern, but they differ noticeably on where a downstream mid-/upper-level high pressure cell takes up residence over the Atlantic either to the northwest or northeast of Bermuda. The farther west/east the high develops will determine how far west/east Florence will eventually move and possibly affect the U.S. east coast beyond the 5-day forecast period.......72 h (hours) and beyond, light shear from the southeast and east along with the development of strong upper-level outflow jets to the north of Florence is expected to create an environment that favors significant and possibly even rapid strengthening.

This meteorological "jargon" basically says an area of high pressure will serve as a blocking and steering mechanism forcing the storm westward. The exact position of the high pressure center will determine when or if there is a turn.

Forecast for FlorenceNOAA

One reason that I am starting to be more aggressive about the threat is that hurricane track forecasts have significantly improved in recent decades. I have written in Forbes on why the track forecasts are somewhat easier to manage than the intensity forecasts. Dr. Michael Ventrice, a tropical meteorologist with IBM/Weather Company, puts it this way,

Hurricane track forecasting at longer leads using weather models is analogous to focusing a pair of binoculars. Eventually you will get focus after a number of attempts.

I am cautious at 10 days out. I am concerned at 5 days out. Something tells me this will not be the last thing I write about Florence. If you live in north Florida, Georgia, the Carolinas, or even Virginia, it is time to think about how you might prepare for a major hurricane landfall. And to make matters worse, there are four more tropical systems of interest in the Atlantic basin as I write this article. We are approaching the statistical peak in Atlantic basin activity so I suppose this should not be surprising.

Dr. J. Marshall Shepherd, a leading international expert in weather and climate, was the 2013 President of American Meteorological Society (AMS) and is Director of the University of Georgia’s (UGA) Atmospheric Sciences Program. Dr. Shepherd is the Georgia Athletic Associati...